Aiseesoft MPEG Converter for Mac can be used to convert your video files into MPEG videos or your MPEG files into a variety of other formats. The application lets you open almost any video or audio file. And the output format support is also quite good. The main reason why I would want to convert a video into the MPEG-1 or MPEG-2 formats is to turn them into a VCD or SVCD. I haven't done that in a long time because I don't own a DVD player anymore, but the application comes with the conversion profiles to let you carry out that task. There are conversion profiles available for many multimedia playback devices as well.
The application comes with a very simple video editor that lets you trim and crop your videos, adjust brightness, contrast and saturation and even add watermarks to them. There is also a video player, which can be used to view videos before conversion. It can take snapshots of your videos and save them in the JPEG format.
In my testing, I converted an MKV file into VCD (NTSC). The process was smooth and quick, and the resulting file looked fine, although the resolution was greatly reduced. But that was to be expected.